This invention relates generally to a tee assembly for use in a raceway system that provides wire and cable management for data, power, audio, and video applications. More specifically, the invention allows for routing power cables and communications cables through the same raceway with both power and communications cables being routable straight through the tee assembly and through a 90 degree bend while maintaining separation between the power and communications cables.
Tee assemblies have traditionally provided raceways with the capability of routing cables or wires both straight and at 90 degree bends through the same raceway system at the same location in the raceway system. This multi-directional capacity has provided efficient space management by minimizing the space that normally would be taken up by the multiple, separate raceway systems required to rout cables in varying directions.
Combining multiple cable routs within the same raceway has its limitations. The UL National Electric Code (NEC) requires power cables to be kept separate from communications cables when installed in raceway systems. Accordingly, raceway ducts and tee assemblies are provided with dividers which separate the power cables from the communications cables. It is often the case, however, that interior office spaces need to be wired for both power and communications-based operations, and thus requiring both power cables and communications cables to be routed to the same locations within the same interior office space. Thus, power cables need to be routed both straight and branched, and communications cables need to be routed likewise. Accordingly, a raceway, likely incorporating a tee assembly, having multiple wireway capacity is most efficient for the job. However, in order to maintain the design and space saving benefits that tee assemblies provide, while maintaining compliance with UL NEC requirements, the power and communications cables must be routed in multiple directions without commingling or entangling the cables.
To prevent commingling or entangling, typical prior art raceway system tee assemblies incorporate a bridge device 10, as shown in FIG. 1. A raceway system having a tee shaped assembly 12 (depicted in FIG. 1 as a base fitting) accommodates linear raceway base members 14a, 14b, and 14c. Raceway members 14a and 14b are aligned along the top of the tee, while the third raceway member 14c is perpendicularly positioned with relation to the first two raceway members 14a and 14b. The bridge 10 is positioned in the tee assembly base fitting 12, and allows power cables A from a first wireway 16 to be routed over communications cables B routed through a second wireway 18, where it is desired that a portion of the communications cables B be routed through the perpendicularly positioned raceway member 14c of the raceway system.
The bridge 10 has a funnel shaped configuration with opposed side walls 20, 20 that are curved to define a funnel shape allowing power cables A to be routed in an arcuate fashion from raceway member 14a and/or raceway member 14b to raceway member 14c. A space 22 is provided behind the bridge device 10 and defines a straight through passageway for power cables A extending between the axially aligned raceway members 14a and 14b. Communications cables B may similarly be routed through the tee assembly 12--i.e., either bent or straight--however, communications cables B merely use the tee assembly base fitting 12 as a guide.
A significant disadvantage of the prior art bridge device 10 is that cable capacity through the bend of the tee assembly is greatly reduced, typically by 50% or more, attributable to the decreased cross-section through the funnel-shaped portion of the bridge. Thus, the cable capacity of the entire raceway system is restricted by the limitations of the tee assembly--i.e., the number of cables routed through the entire raceway system is dependent upon the number of cables that can be accommodated through the bend of the tee assembly. In order to increase the cable capacity of a raceway system with a tee assembly incorporating a bridge device, a tee assembly with a larger cross-sectional capacity is required (i.e., increasing the cross-section of the wireways at the bend portion of the tee assembly), which would protrude out from the raceway. This is undesirable in situations where the raceway system should be discrete and use as little office space as possible.
Another disadvantage of the prior art bridge device 10 is the lack of a smooth transition for cables being routed from a linear raceway member 14a over the bridge 10 and into another linear raceway member 14c. The prior art bridge 10 is provided with a flat planar section 24 supported at an intermediate position between the base surface and the top surface by sidewalls on each side of the planar surface. Thus, a cable B running adjacent the base surface of the tee assembly must not only be bent through the funnel-shaped portion of the bridge, but it must be contorted upwardly into order to pass across the planar surface 24 of the bridge 10. Cables with less flexibility are less likely to follow a path through a raceway that takes up a minimal cross-sectional space when they are subjected to multiple contortions and bends within a relatively small segment of the cable. Accordingly, bridge devices that require the cables to "step-up" and "step-down" in order to pass across the bridge device having proven undesirable where maximization of the cross-sectional capacity of a raceway is preferred.
U.S. Pat. No. 5,753,855 to Nicoli et al. attempts to alleviate the drawbacks of the bridge device shown in FIG. 1, by expanding the width of the funnel-shaped portion. However, the Nicoli et al. bridge device does little to overcome the step transition drawback typical of the prior art bridge devices.
Another disadvantage of prior art bridge devices is that they often must be secured to the tee assembly and provide little flexibility of use. Most bridges must be smaller than the tee assembly so as to leave channel space for multiple wireways. To prevent shifting within the assembly, the bridge is often welded, screwed or bolted to the assembly (as shown in FIG. 1 by bracket 26). Alternatively, the bridge is provided with sidewalls that run flush with the sidewalls of the tee assembly to restrict lateral shifting of the bridge (as disclosed in Nicoli et al.).
Many prior art tee assemblies also have not proved suitable for accommodating fiber optic cable. Fiber optic cable cannot accommodate a bend radius of less than 2 inches when routed through a bend of a tee assembly. Such cable can be damaged when routed through a bend having a sub-optimal radius of curvature. Thus, certain bridge designs whereby fiber optic cables may be contorted through sharp angles due to limited use of the space within the tee assembly have proved undesirable.
The chief aim of the present invention is to provide a tee assembly which is not only capable of accommodating fiber optic cable with no more than a two inch radius bend, but which can separate wires routed through the assembly without significantly reducing the cable capacity of the raceway system.